In the summer of 1969, 400,000 hippies, bohemians, artists, and revolutionaries of all stripes descended on a small dairy farm in Bethel, New York for Woodstock, an event celebrating peace, youthful rebellion, and a general disregard for personal hygiene. The Woodstock Music and Art Fair was widely regarded as a watershed moment in the counterculture movement and in modern musical history. But by the time the party officially kicked off 48 years ago on Aug. 15, disaster was poised to strike, and it would have if not for the intervention of an unlikely ally: the U.S. Army.